| 摘要 |
556,246. Automatic control systems for electric motors. JUHLIN, G. A., and METROPOLITANVICKERS ELECTRICAL CO., Ltd. March 23, 1942, No. 3847. [Class 38 (iv)] [Also in Group XXXVII] Speed.-The generator WG of a Ward-Leonard system, particularly for an electrical winder installation is controlled by a sensitive and rapidly responding auxiliary generator such as a metadyne or D.C. machine of armature reaction excited type EA so that if the speed of the motor M is not in conformity with the setting of a speed control member WER, differentially related components of the excitation of 'the auxiliary generator will rectify the error. One excitation winding EF2 may be subjected to a voltage representing the setting of the speed control member which may accordingly be coupled to a potentiometer element EGT and an opposed excitation winding EF1 subjected to a voltage representative of motor speed namely to the tachometer generator TGA. Alternatively a single excitation winding on the auxiliary generator may be subject to opposed voltages representative of the setting of the speed control member and of the motor speed. Fig. 2 (not shown) illustrates a complete system in which the metadyne has a further field winding excited in accordance with the difference between a predetermined voltage from a potentiometer and the voltage across a resistance in the armature circuit of the motor whereby a predetermined overload limitation is obtained under both normal and regenerative operation thereof. |
